1. Field of the Invention
The present invention generally relates to a camera and, more particularly, to a camera having a multi-point distance measuring device for automatically correcting the parallax of a so-called lens shutter camera which has an optical system different from a photographing optical system.
2. Description of the Related Art
As is well known, a lens shutter camera, which has been conventionally used, has a finder device including a finder optical system different from an optical system of a photographing lens.
FIG. 11 shows an example of the conventional lens shutter camera. Referring to FIG. 11, a finder device 2 and a photographing lens 3 are arranged on a camera main body 1, so that their optical axes are separated from each other. For this reason, an object image (finder image) observed in a photographing frame via the finder device 2 and an actually photographed object image are undesirably shifted from each other due to a parallax, as shown in FIGS. 12A, 12B, and 12C.
For example, when a flower 4 as an object is to be photographed in a state shown in FIG. 12A, and when an optical axis OF of the finder device 2 and an optical axis OL of the photographing lens 3 are parallel to each other, and the finder device 2 and the photographing lens 3 are arranged at positions separated by a distance FL, even if an image of the flower 4 is observed in the finder device 2, as shown in FIG. 12B, the actually taken picture becomes an offset object image, as shown in FIG. 12C. Therefore, a photographer cannot often take a desired picture using the conventional lens shutter camera.
In order to solve this problem, the following technique is known. That is, as shown in FIG. 13, an inclination angle .theta. is determined based on an object distance L and the distance FL between the finder device 2 and the photographing lens 3, and the optical axis of the finder device is inclined through the angle .theta., so that a point observed by the finder device 2 coincides with a point observed by the photographing lens 3. As an example of this technique, Jpn. Pat. Appln. KOKAI Application No. 1-147439 discloses, a parallax correction device for a camera, which sets the inclination angle .theta. by utilizing a Drehkeil type prism.
In the case of a camera in which an auto-focus (AF) distance measuring device measures the distance to an object on an optical axis different from those of the finder device and the photographing lens, a parallax is also generated between the finder device and the AF distance measuring device, and a point observed via the finder device and the actual distance-measuring point become different from each other in the same principle as that shown in FIG. 12A.
In order to solve this problem, in the parallax correction device for a camera of Jpn. Pat. Appln. KOKAI Application No. 1-147439 described above, an arrangement for measuring the distance to an object on the optical axis of the finder device 2 is disclosed.
Furthermore, Jpn. Pat. Appln. KOKAI Application No. 5-5833 discloses a technique for performing a macro photographing operation on the basis of distance measuring information of a surrounding region while ignoring distance measuring information of its central region by utilizing a multi-point AF mechanism.
However, when a distance measuring device is assembled in the finder device, the structure of the finder device becomes complicated, and the optical path must be split into those for the finder connection and distance measuring systems. For this reason, such an arrangement tends to impair observability of the finder device and the S/N ratio of a distance measuring system.
When the optical axis of the finder device is switched on a distance measuring operation, a photographer must re-determine the composition of a picture. During this time, the distance to an object may be changed.
Furthermore, in the parallax correction device for a camera of Jpn. Pat. Appln. KOKAI Application No. 1-147439 described above, a distance re-measuring button is provided to a release button to allow re-measurement of the distance. However, when the optical axis of the finder device is switched for each distance measuring operation, a photographer must perform very troublesome operations.
Note that Jpn. Pat. Appln. KOKAI Application No. 5-5833 does not mention about any parallax generated between the finder device and the photographing lens.